Momentary break switch comprising a delay means and/or a shunt connection



6, 1958 c. DIEHL MOMENTARY BREAK SWITCH COMPRISING A DELAY MEANS AND/OR A SHUNT CONNECTION Filed Aug. 10, 1967 CONRAD DIEHL QM am %MM4 ATTORNEYS United States Patent ice 3,396,256 MOMENTARY BREAK SWITCH COMPRISING A DELAY MEANS AND/ OR A SHUNT CONNECTION Conrad Diehl, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed Aug. 10, 1967, Ser. No. 659,666 Claims. (Cl. 200-160) ABSTRACT OF THE DISCLOSURE A momentary break switch is provided wherein an actuation of a push button plunger forces a conductive blade between a pair of normally closed contacts. A circuit current path is maintained between the contacts while the blade is therebetween but is broken when the blade passes wholly from between the contacts, during the increment of time it takes for the contacts to snap together. One of the contacts, the movable one, is mounted on a pivoted rocker member which provides for movement of the movable contact and incorporates an inertia delay in the closing movement, thus adding time delay. A shunt connection different from the connection made through the two contacts is also provided, the shunt connection being broken when the push button plunger is actuated.

The present invention relates to an electrical switch mechanism and more particularly to an electrical switch which is normally closed but is opened momentarily upon depression of an associated push button.

The utilization of make and break switching arrangements has become increasingly important with the rapid development of electrical control systems. With the advent of increased technology and sophistication in systems of this type, a demand has been created for switches which will operate in a uniform manner during repetitive use over an extended period of time.

It is therefore an object of the present invention to provide an improved electrical switch which is normally closed and which can be opened only momentarily and for a substantially uniform increment of time upon movement of an associated push button or other actuating means, regardless of the rate of movement thereof.

It is a further object of the present invention to provide a momentary break, electrical switch which is characterized by simplicity of construction and ease of operation, such switch during its normal operation cycle being continuously closed except for a brief predetermined increment of the time during which the associated push button is depressed.

One problem encountered with momentary break switches is that these switches in certain applications may not furnish sufiicient open time to enable circuit elements used therewith to de-energize as intended. For example, in systems utilizing elements such as solenoids which are reset or de-energized by opening a momentary break switch, the break switch must open the circuit for a sufficiently long period of time to allow the armature of the solenoid to return to its initial rest position.

It is, therefore, a further object of the present invention to provide an electrical switch mechanism of the type described which has a definite time delay in its momentary break to allow sufificient time for control of such circuit elements.

Another problem encountered with momentary break switches is that these switches, because of their relatively delicate construction, may possibly be opened inadvertently by shocks or vibrations.

It is, therefore, an additional object of the present invention to provide a switching mechanism of the type 3,396,256 Patented Aug. 6, 1968 described with means for ensuring that the circuit completed by the momentary break switch contacts will not be opened inadvertently even when the momentary break switch contacts themselves are inadvertently opened, for instance, by shocks or vibrations.

The foregoing objects have been attained by the provision of a pair of normally closed switch contacts which are urged apart upon depression of a push button or other actuating means by a blade member of electrically conducting material, the blade member being disengaged from the contacts as the push button reaches or nears the end of its depressed path, thus allowing the contacts to spring together but interrupting the electrical contact therebetween prior to their re-engagement. In accordance with one aspect of the invention, delay means are 'provided for delaying the springing together of the contacts. In a presently preferred embodiment, the delay means comprises a pivoted rocker member upon which one of the switch contacts is mounted, whereby the inertia of the rocker member slows the closing movement of the rockermounted contact toward the other contact.

In accordance with another aspect of the present invention a second path is provided between the electrical conductors of the circuit completed by the momentary break switch to ensure that the circuit will remain closed even if the momentary switch contacts are inadvertently opened. In a presently preferred embodiment of the invention a second pair of shunt contacts are provided which, individually, are electrically common to respective individual main contacts of the momentary switch. The shunt contacts are opened by a member actuated by the push button before the main contacts are opened, and remain open for a time after the main contacts are closed. In accordance with a second embodiment of this aspect of the invention, the second path is completed through the blade member in its normal rest position, between one main contact and another shunt contact electrically commom with the other main contact.

The present invention is an improvement of the subject matter disclosed in copending application Ser. No. 570,206 (Phillip N. Crawford et al.), assigned to the same assignee as the present invention.

The switching mechanism of the present invention is particularly suited for use in a motion picture projector system of the type disclosed in application Ser. No. 659,718, entitled Motion Picture Projector System, filed concurrently herewith by Richard C. Painton and assigned to the same assignee as the present invention. As incorporated in the projector system of the copending application the switch of the present invention serves as a remote control momentary start or reset switch for the projector. The projector system includes a relay-controlled stop solenoid which must be reset to the de-energized position thereof to permit resumed advancement of filmstrip. The present invention provides a momentary break switch wherein the open time of the switch (e.g., two milliseconds) is sufiiciently long to permit de-energization of the stop solenoid of the projection system.

Other objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of two embodiments of the invention, reference being made to the accompanying drawings wherein:

FIG. 1 is an exploded front perspective view of the presently preferred embodiment of the invention.

FIG. 2 is an exploded rear perspective view of a second, but similar, embodiment of the invention.

FIG. 3 is an exaggerated schematic drawing illustrating the operation of the invention as embodied in FIGS. 1 and 2.

Referring to FIG. 1 of the drawings, the momentary break switch mechanism comprises a first main contact generally designated and a second main contact generally designated 12. It is contemplated that the switch and switch actuator in commerical practice will be located on the underside of a remote control box and for this reason the elements are shown upside down from what might be regarded as their normal positions.

Contact 12 comprises a base portion 14 rigidly atfixed to a wall 18 of an enclosure for the switch mechanism, which may be the plastic remote control box, and an upright contact member 16 generally perpendicular to the base portion 14 and the enclosure wall 18. An electrical conductor 20 is afiixed to base portion 14 by any suitable means, such as soldering. The assembly further comprises a member 19 which includes a first portion 19a in contact with and extending outwardly under base portion 14, a second portion 19b extending perpendicularly upwardly from portion 19a and a third, contact portion 190 extending perpendicularly from said second portion 19b and generally parallel to base portion 14.

Main contact 10 is mounted on or forms part of a rocker member 22 which comprises an elongated body in the form of a flat bar pivotally connected by a rivet or the like at 24 to the upright portion 26 of a fixed bracket member 25. Bracket member further comprises a base portion (not visible in FIG. 1, but identical to 28 in FIG. 2 rigidly afiixed to wall 18 by suitable means. Contact 10 and rocker member 22 are preferably of single piece construction, with contact 10 extending upwardly from the upper edge of rocker 22 at an angle thereto and then along a line generally perpendicular to the plane of the surface of the rocker member, terminating in a contact blade 10a. The surface of the contact blade 10a forms an angle with the vertical when in the normal position and oriented as shown in FIG. 1. This angle is best illustrated in FIG. 3, in relation to vertical member 16. Rocker member 22 has end portions 22a bent outwardly from the surface of member 22 generally at right angles thereto to increase its inertia.

Upright contact portion 16 of contact 12 is located adjacent the rocker member 22 generally at right angles thereto, and contact blade 10a contacts member 16 when in the normal closed position.

A flexible spring arm 30 extends upwardly from a base member 32 rigidly affixed to enclosure wall 18, and generally forms an angle with the base member 32 and enclosure Wall 18 equal to the-complement of that formed by contact blade 10a and upright contact portion 16 of contact 12. An electrical conductor 36 is affixed to base member 32 by suitable means such as soldering. Base member 32 further comprises a member extending outwardly at 32a from base member 32 in the same plane, upwardly at 32b in a perpendicular plane, and outwardly from 32b in a plane perpendicular thereto to terminate in shunt contact portion 320, the plane of contact portion 320 being generally parallel to the plane of base member 32. Spring arm 30 urges contact blade 10a into engagement with upright portion 16 of contact 12, and shunt contact 320 of base member 32 contacts shunt contact 19c of member 19. Contacts 190 and 320 are perpendicular to one another and lie generally in the same plane, with contact 19c resting upon contact 320.

It will be appreciated that, with elements 10, 12, 19, 30 and 32 being constructed of electrically conductive material and wall 18 of non conductive material. There are two electrical paths between electrical conductors 20 and 36, a primary path through base portion 14 and upright portion 16 of contact 12, contact blade 10a, spring arm 30, and base member 32 and a shunt path from base member 14 and member 19 to base member 32 through portions 32a, 32b thereof by way of contacts 19c and 320. Therefore, if the primary path through contacts 10 and 12 is broken inadvertently as through jarring or vibration, the shunt path will provide a path for circuit current flow, and thus an electrical circuit (not shown) included between conductors 20 and 36 will not be opened.

The actuating means for switch contacts 10 and 12, shown at the left hand side of FIG. 1, comprises an actuating assembly 37 which includes a push button plunger 41 extending through enclosure wall 18 into a cylindrical hollow in an assembly housing 44. A collar 39, having the configuration shown and disposed between enclosure wall 18 and an actuating member 40, surrounds and is fixed to plunger 41. A biasing spring 42 is disposed between the surface of a base portion 40a of actuating member 40 and an upper surface of housing 44. Spring 42 is aflixed at one end to member 40 and at the other end to a spring end mount 46 located in an upper surface of housing 44, and functions to bias plunger 41, collar 39, and actuating member 40 downwardly to the rest position shown in FIG. 1, while biasing member 40 rotationally about plunger 41 in a counterclockwise direction as viewed downwardly in FIG. 1.

Actuating member 40 is constructed of conductive material and includes an upright portion 48b, extending perpendicularly upward from base portion 40a, an actu- 'ating blade 40c and a shunt lever 40d extending outwardly of upright portion 40b. The surface of upright portion 40b is generally parallel to the surface of rocker member 22, and actuating blade 400 extends generally perpendicularly outward from upright portion 40b but is shaped to form an angle with the perpendicular substantially equal to the angle formed by upright portion 16 of contact 12 and contact blade 10a as shown in FIG. 3. Shunt lever 40d extends outwardly from upright portion 40b in substantially the same plane.

When the switch mechanism is assembled actuating blade 400 contacts the surface of upright portion 16 of contact 12 beneath contact blade 10a as shown generally in FIG. 3 while shunt lever 40a is situated below shunt contact 190.

In operation, as push button plunger 41 is depressed actuating member 40 moves upwardly against the biasing action of spring 42, causing a like movement of actuating blade 40c and shunt lever 40d. The nature and effect of the movements of the last-named members will be considered individually.

The movement of actuating blade 40c is generally represented in FIG. 3, and, as shown, may be divided into three movement paths, A, B and C. During movement along path A, which extends between the normal rest position of blade 40c and the end position thereof, switch contacts 10 and 12 are opened. Thus as movement takes place along path A, actuating blade 40c encounters contact blade 10a and cams contact blade 10a away from the surface of upright portion 16 of contact 12, against the biasing force of spring arm 30. At this time although contacts 10 and 12 are opened, there is still current flow between contacts 10 and 12 by way of blade 400. This current flow will continue as long as actuating blade 400 is positioned between the contacts. As actuating blade 40c continues movement along path A, contact blade 10a rides over the inclined surface of blade 40c until blade 40c travels wholly out from between and past contacts 10 and 12. At this time contact blade 10a snaps back into contact with contact 12. Thus for a brief increment of time current flow between contac-ts 10 and 12 ceases, this time being the time required for contact blade 10a to snap back into contact with contact 12.

The length of time required for contact 10 to close with contact 12 is increased by the fact that contact 10 is connected to rocker member 22. Rocker member 22 is pivoted by the camming eifect of actuating blade 40c on contact blade 10a and thus must pivot back into the normal position shown for contact 10 to close with contact 12. The inertia of rocker member 22 impedes the rotation of member 22 and associated contact 10, and thus the open time for the switch is increased. End portions 22a of rocker member 22 serve to increase the inertia of rocker member 22 as well as to provide balance. The open time provided by an exemplary structure is on the order of two milliseconds.

Returning to the operation of the actuating blade 40c, after travel between and past the contacts and 12, movement continues to the end position dictated by the movement of the plunger 38. As plunger 38 is released, spring 42 forces actuating member 40 in the opposite direction, i.e., downwardly, and actuating blade 40c begins its return movement to the normal position thereof. As movement takes place along path B shown in FIG. 3, blade 10a again encounters contact blade 40c and at this time, because of the inclined configurations of the two blades, blade 40c rides over the outer surface of contact blade 10a, and thereafter blade 40c snaps back into contact with the member 16 as indicated by path C in FIG. 3. During this return movement, member 40 and its arm 400, of course, pivot about and relative to plunger 41, first against the bias of spring 42 and then in the direction of the bias. Thus, during the entire return path of blade 40c along paths B and C contacts 10 and 12 remain closed.

As to'the operation of shunt lever 40d, as plunger 41 is actuated, lever 40d moves upwardly to engage contact 19c of member 19 and lift contact 190 from contact with shunt contact 320, thereby interrupting the shunt path formed through contacts 19c and 320. As plunger 38 is released, spring 42 causes downward movement of blade 40d and disengagement of blade 40d from contact 190. Contact 19c returns to engagement with contact 320 and the shunt path is restored. It will be appreciated that the shunt path is broken, relatively speaking, just before the primary path between contacts 10 and 12 is broken and subsequently closed after the primary path is restored. Thus contacts 190 and 32c provide an auxiliary shunt path for the circuit current which will function to keep the circuit closed in the event that the primary path is inadvertently destroyed, but which is opened during normal intended opening of the primary path.

The embodiment shown in FIG. 2 is substantially identical to the embodiment of FIG. 1 except for the details of the shunt path, and accordingly most of the description of FIG. 1 applies also to FIG. 2. Those elements of FIG. 2 which correspond to FIG. 1 have been designated by the primes of the reference numerals used in FIG. 1. The general sequence of operations is identical to the embodirnent of FIG. 1.

Referring to FIG. 2, shunt contact 32c, corresponds in function and general structure to shunt contact 320 of FIG. 1. However, in the FIG. 2 embodiment, actuating lever 40c functions as the second shunt contact by bearing against shunt contact 32c and upright member 16 of contact 12 when in its normal rest position. The FIG. 2 embodiment thus does not include members corresponding to shunt lever 40d and shunt contact 19:: of FIG. 1.

With the FIG. 2 embodiment assembled and in the rest position, the shunt path is completed from shunt contact 320' through actuating lever 400 to member 16 of contact 12', since lever 40c is biased by spring 42' downwardly against shunt contact 320' and pivotally about the axis of actuating member 40 into contact with member 16'. When pushbutton 41' is actuated, lever 40c moves upwardly away from shunt contact 32c, thus opening the shunt path, and thereafter continues upwardly to effect momentary opening of the main contacts as set forth in the description of the FIG. 1 embodiment, and as depicted generally in FIG. 3. Upon release of the pushbutton, lever 40c returns to its shunt completing position under the translational and pivotal bias of spring 42'.

It will be understood by those skilled in the art that the embodiments of the invention shown and described herein are subject to various modifications without departing from the scope and spirit of the invention. Accordingly, it should be understood that the invention is not limited by the exemplary embodiments shown and described, but rather only by the subjoined claims as construed in light of the foregoing specification and drawings.

I claim:

1. An electrical switch mechanism for forming connections between electrical conductors, said mechanism comprising first and second normally closed switch contacts forming a first connection between the electrical conductors, actuating means movable over a predetermined path from a first position to a second position, electrically conductive means responsive to movement of said actuating means for passing between said contacts so as to separate said contacts while maintaining a conductive path therebetween but to interrupt said conductive path for a predetermined time only while passing wholly from between said contacts, and means controlled by said actuating means for normally maintaining a shunt connection between the conductors and breaking said shunt connection during movement of said acuating means.

2. An electrical switch mechanism in accordance with claim 1 wherein said shunt connection is made through said electrically conductive means.

3. An electrical switch mechanism in accordance with claim 2 wherein said shunt connection is made from a third contact electrically common to said first contact, through said electrically conductive means, to said second contact.

4. An electrical switch mechanism in accordance with claim 3 wherein said electrically conductive means rests on said third contact when in said first position and wherein said third contact is electrically connected to said first contact through flexible spring means, said flexible spring means further serving to bias said first contact into engagement with said second contact.

5. An electrical switch in accordance with claim 1 wherein said shunt connection is broken by means responsive to the movement of said actuating means.

6. An electrical switch in accordance with claim 1 wherein said shunt connection is made through a third contact electrically common to said first contact and a fourth contact electrically common to said second contact, independently of said electrically conductive means.

7. An electrical switch in accordance with claim 6 wherein said third contact comprises a member having a portion lying in a plane generally perpendicular to the path of movement of said actuating means, said fourth contact comprises a member having a portion also lying in a plane perpendicular to said path of movement of said actuating member, said portion of said fourth contact making electrical contact with said portion of said third contact, and wherein said actuating means includes means for separating said fourth contact portion from said third contact portion to break the electrical contact therebetween upon movement from said first position toward said second position.

8. An electrical switch mechanism in accordance with claim 7 where said first contact is movable and is connected to rocker means for providing an inertial delay in the closing movement of said first contact toward said second contact after said electrically conductive means passes from between said first and second contacts.

9. An electrical switch mechanism in accordance with claim 1 wherein said electrically conductive means comprises a blade member having an angled end portion for exerting a contact-opening camming action upon said first contact as said blade member passes between said contacts and for permitting said contacts to snap together after passing from therebetween, thereby briefly interrupting the conductive path between said contacts and wherein said second connection includes third and fourth contacts electrically common with said first and second contacts, respectively.

10. An electrical switch mechanism comprising, first and second switch contacts biased to a normally closed state, actuating means movable over a predetermined path from a first position to a second position, electrically conductive means responsive to movement of said actuating means for passing between and separating said contacts but maintaining the electrical connection while between the contacts, and breaking the electrical connection momentarily when passing from between said contacts until said contacts return to their normally closed state, and delay means connected to said first switch contact for delaying the return of said contacts to said normally closed state for a predetermined time.

11. An electrical switch mechanism according to claim 10 wherein said delay means comprises pivoted rocker means mounting said first contact for movement away from and toward said second contact and providing an inertial delay in the movement of said first contact.

12. An electrical switch mechanism in accordance with claim 11 wherein said electrically conductive means comprises a blade member having an angled portion for exerting a contact-opening camming action upon said first contact as said blade member passes between said contacts and for permitting said contacts to snap together after passing from therebetween, and wherein there is included spring means for biasing said first contact into engagement with said second contact.

13. A switching mechanism in accordance with claim 11 wherein said rocker means comprises an elongated bar portion and a pair of outwardly extending end portions.

14. An electrical switch mechanism comprising a first movable contact and a second contact forming a first electrical connection between conductors, means biasing said first movable contact into engagement with said second contact, means defining a normally closed shunt connection between said conductors, and selectively actuatable means for, upon actuation, (1) breaking said shunt connection, and (2) moving said first movable contact away from and out of engagement with said second contact by a predetermined fixed distance while maintaining the electrical connection therebctween, (3) abruptly and simultaneously releasing said first movable contact and breaking the electrical connection between said contacts for a predetermined period equal to the time required for said first movable contact to snap back into engagement with said second contact, and (4) remaking said shunt connection.

15. A switch mechanism as claimed in claim 14 further comprising a pivotally mounted rocker arm supporting said first movable contact for movement therewith so as to incorporate an inertial delay in the snap-back movement of said first contact upon release by said actuatable means.

References Cited UNITED STATES PATENTS 2,198,659 4/1940 De Vincenzi. 2,586,056 2/1952 Kling et al. 200 2,616,009 10/1952 Roeser 200160 2,809,261 10/ 1957 Xenakis 200-160 ROBERT K. SCHAEFER, Primary Examiner.

H. BURKS, Assistant Examiner. 

